In the case of fuel injectors having a so-called hydraulic stop, there is no direct contact between the armature and the pole piece when the fuel injector opens since the fuel flows between the armature and the pole piece and, in the process, exerts a hydraulic force, which opposes the magnetic force, on the armature. Said two forces cancel each other out in the open state of the fuel injector, so that there is a gap having a substantially constant width between the armature and the pole piece. However, if the hydraulic force is too low, for example in the case of a defective fuel pump (high-pressure pump), the necessary gap width cannot be maintained and the injection of fuel is blocked after a very short time on account of the correspondingly high drop in pressure in the small gap (or closed gap in a worst-case scenario).